Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Acinetobacter baumannii Clinical Isolates in South Africa

Abstract

Introduction. Carbapenem-resistant Acinetobacter baumannii has been responsible for an increasing number of hospital-acquired infections globally. The study investigated the prevalence of carbapenemase-encoding genes in clinical multidrug-resistant A. baumannii strains. Materials and Methods. A total of 100 nonduplicate multidrug-resistant A. baumannii strains were cultured from clinical samples obtained from healthcare facilities in the O. R. Tambo district. The strains were confirmed by detecting the intrinsic blaOXA-51-like gene. Antimicrobial susceptibility testing was performed by VITEK® 2 and autoSCAN-4 systems. The MIC of imipenem and meropenem was rechecked by E-test. Colistin MIC was confirmed by the broth microdilution method. Real-time PCR was performed to investigate the presence of carbapenemase-encoding genes. Results. Most strains showed high resistance rates (>80%) to the antibiotics tested. Resistance to amikacin, tetracycline, and tigecycline were 50%, 64%, and 48%, respectively. All strains were fully susceptible to colistin. The blaOXA-51-like was detected in all strains whilst blaOXA-23-like, blaOXA-58-like, blaOXA-24-like, blaIMP-1, blaVIM, and blaNDM-1 were found in 70%, 8%, 5%, 4%, 3%, and 2% of strains, respectively. None of the tested strains harboured the genes blaSIM and blaAmpC. The coexistence of blaOXA-23-like, and blaIMP-1 or blaOXA-58-like was detected in 1% and 2% strains, respectively. A distinct feature of our findings was the coharbouring of the genes blaOXA-23-like, blaOXA-58-like, and blaIMP-1 in 2% strains, and this is the first report in the Eastern Cape Province, South Africa. The intI1 was carried in 80% of tested strains whilst ISAba1/blaOXA-51-like and ISAba1/blaOXA-23-like were detected in 15% and 40% of the strains, respectively. The detection of blaOXA-23-like, ISAba1/blaOXA-51-like, ISAba1/blaOXA-23-like, and blaOXA-23-like, blaOXA-58-like, and blaIMP-1 carbapenemases in strains had a significant effect on both imipenem and meropenem MICs. Conclusions. Results showed a high level of oxacillinases producing A. baumannii circulating in our study setting, highlighting the need for local molecular surveillance to inform appropriate management and prevention strategies.

Efflux Pump Activity and Mutations Driving Multidrug Resistance in Acinetobacter baumannii at a Tertiary Hospital in Pretoria, South Africa

“…is study results reveal a high resistance to most of available antibiotics used by clinicians in management of A. baumannii infections (cefotaxime 89%, ceftazidime 85%, cefepime 85%, piperacillin + tazobactam 76%, imipenem 83%, meropenem 83%, ciprofloxacin 83%, gentamycin 81%, and trimethoprim-sulfamethoxazole 82%) (Figure 1). e findings are similar to several reports made by different researchers within the region [54][55][56] and globally [58]. In their published report on the district of Oliver Reginald Tambo in the Eastern Cape Province of South Africa, Anane et al [55] highlighted that A. baumannii strains showed resistance rates above 80% against the same antibiotics tested in this current study.…”

“…e findings are similar to several reports made by different researchers within the region [54][55][56] and globally [58]. In their published report on the district of Oliver Reginald Tambo in the Eastern Cape Province of South Africa, Anane et al [55] highlighted that A. baumannii strains showed resistance rates above 80% against the same antibiotics tested in this current study. Similarly, Lowe et al [57] in Tshwane district in Gauteng province of South Africa reported high prevalence of resistance (69-90%) of A. baumannii strains to the same antibiotics tested in the current study.…”

“…The findings are similar to several reports made by different researchers within the region [ 54 – 56 ] and globally [ 58 ]. In their published report on the district of Oliver Reginald Tambo in the Eastern Cape Province of South Africa, Anane et al [ 55 ] highlighted that A . baumannii strains showed resistance rates above 80% against the same antibiotics tested in this current study.…”

Molecular epidemiology of carbapenem‐resistant Acinetobacter baumannii isolated from three major hospitals in Jordan

“…[32][33][34][35] Overexpression of OXA-51 and OXA-23 has been associated with insertion (IS) elements located upstream of their gene. [36][37][38] One of the most common IS elements is the ISAba1, which promotes the expression of these genes and modifies their mobility. 37 Numerous studies reported that A. baumannii isolates bearing ISAba1, especially upstream bla OX A-51…”

Genotypic and Phenotypic Characterization of Novel Sequence Types of Carbapenem-Resistant Acinetobacter baumannii, With Heterogeneous Resistance Determinants and Targeted Variations in Efflux Operons

“…Several reports on the increased incidences and propagation of carbapenem-resistant A. baumannii (CRAB) across continents in the last few years have received physicians’ attention. Carbapenem resistance is a severe problem affecting Africa’s health-care system, where the occurrences have surged from <1 to 60% among Gram-negative bacteria ( Anane et al, 2020 ). In a recent study carried out in Nepal’s tertiary care hospital, of the 177 A. baumannii studied, nearly 91% of them exhibited carbapenem resistance ( Devkota et al, 2020 ).…”